1. Field of the Invention
The present invention relates to an elongated key support mechanism including a guide mechanism having two mutually coupled link members for supporting an elongated key, such as a space key, and for guiding vertical movement of a key top of the elongated key by scissors-like movement of the guide mechanism.
2. Description of the Related Art
Japanese Laid-Open Patent Publication No. HEI-6-36648 discloses an elongated key support mechanism 100 shown in FIG. 1. The elongated key support mechanism 100 includes: an elongated key top 101 formed elongated in a lengthwise direction, a holder member 130, and a guide support mechanism 106 disposed between the key top 101 and the holder member 130. The guide support mechanism 106 is for supportingly guiding vertical movement of the elongated key top 101 and includes two hinge-like members 107, 108 that are pivotably supported about a common axis so as to open and close in a scissors-like manner to enable vertical movement of the key top 101.
As shown in FIG. 2, the hinge member 107 is formed in a substantial C shape. The hinge member 107 includes a connection rod 113 formed to a length corresponding to the length of the elongated key top 101 and a pair of link members 109 provided at opposite ends of the connection rod 113. The connection rod 113 and the pair of link members 109 are integrally formed together. An axial protrusion 112 is provided to a substantially central position of each of the link members 109. The axial protrusions 112 protrude inward toward each other.
As shown in FIG. 3, the hinge member 108 of the guide support member 106 includes a connection rod 121 and a pair of link members 117 provided at opposite ends of the connection rod 121. The connection rod 121 and the pair of link members 117 are formed integrally together. The connection rod 121 is formed to a length corresponding to the length of the elongated key top 101 so that the pair of link members 117 are separated by distance corresponding to the length of the elongated key top 101. The hinge member 108 further includes a depression bar 118 connected between the link members 117 at the substantial center of opposing surfaces of the link members 117. The depression bar 118 is integrally formed with the link members 117. An axial hole is formed near the center of an outward facing edge of each link member 117.
When the elongated key support mechanism 100 is assembled, the pair of axial protrusions 112 are pivotably fitted in corresponding ones of the pair of axial holes 120 so that the hinge members 107, 108 of the guide support member 106 are freely openable and closable in a scissors-like manner. As shown in FIG. 4, the depression bar 118 is mounted on an upper surface of a rubber spring 131 so that when the elongated key top 101 is pressed downward, the hinge members 107, 108 pivot in a scissors-like manner in association with downward movement of the elongated key top 101. As a result, the rubber spring 131 is compressed downward so that electrical contact is achieved to perform a switching operation.